I've been having this issue lately. In the morning I'll open up the computer and hit esc to wake it from sleep. sometimes it's all fine and comes to life, but often it will come to life, shows say 60% battery life. I'll then start doing something with the computer and the screen will just go dark. I can't get it to come back to life and hitting esc or power doesn't do anything until finally a dead battery indicator pops up on the screen. So, I'll plug the laptop in and the indicator will start to show charging and about 1-2 minutes later it will allow me to start it again from ? sleep ? and then login and what does the battery charge then say 62%. So the battery isn't actually dead, but the computer THINKS it is dead. this has all started happening just since the install of el capitan. When I check the battery, there are only 500 cycles on it, and coconut says it's over 80%, I can get it with a full drain and re-charge up to about 89%..and it usually works pretty well. but mornings, not it's best time. rMBP 15" 2012 model, 2.6. 16GB, etc.